Fossa ovalis penetration

ABSTRACT

A wall ( 39 ) of a catheter ( 38 ) (a) includes a braided portion ( 41 ) having an outer surface ( 45 ), an inner surface ( 47 ), and a braided interior ( 53 ) between the outer and inner surfaces ( 45, 47 ), and (b) is shaped to define first and second longitudinally-running channels ( 27   a,    27   b ) therethrough. A distal portion of the catheter ( 38 ) is shaped to define first and second lateral openings ( 26   a,    26   b ). An angle between (a) a first line ( 76 ) running between the first and second lateral openings ( 26   a,    26   b ), and (b) a second line ( 78 ) that is parallel to a central longitudinal axis of the catheter ( 38 ) when the catheter ( 38 ) is straight, is between 30 and 150 degrees. A flexible longitudinal member ( 14 ) passes from a proximal portion of the catheter ( 38 ) to the distal portion via the first channel ( 27   a ), out of the first channel ( 27   a ) via the first lateral opening ( 26   a ), into the second channel ( 27   b ) via the second lateral opening ( 26   b ), and from the distal portion to the proximal portion via the second channel ( 27   b ).

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is the U.S. national phase of PCT/IL2015/051026,filed Oct. 14, 2015, which (a) claims priority from and is acontinuation-in-part of U.S. application Ser. No. 14/513,435 to Sapir etal., filed Oct. 14, 2014, now abandoned, and (b) claims priority fromU.S. Provisional Application 62/095,150, filed Dec. 22, 2014, both ofwhich are assigned to the assignee of the present application and areincorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates in general to apparatus and methods fordelivering therapeutic devices to the left ventricle of the heart. Morespecifically, the present invention relates to apparatus and methods forpenetrating the fossa ovalis for the purpose of delivering therapeuticdevices.

BACKGROUND

Various pathologies call for the delivery of therapeutic devices, e.g.,valve repair or valve replacement devices, to the left atrium or leftventricle of the heart (i.e., the left side of the heart). In manyapplications, therapeutic devices are delivered to the left side of theheart by being passed through the vena cava, into the right atrium, andthrough the interatrial septum. Such delivery calls for apparatus andmethods for puncturing the interatrial septum. In many applications, thedesired site for puncture lies in the fossa ovalis, a region of theseptum containing tissue of lesser thickness than is typical of the restof the septum.

SUMMARY OF THE INVENTION

Applications of the present invention include apparatus for puncturing afossa ovalis. The apparatus includes a catheter shaped to define acatheter lumen. The wall of the catheter includes a braided portion, andis shaped to define first and second longitudinally-running channelstherethrough. A distal portion of the catheter is shaped to define firstand second lateral openings, which are typically approximatelyequidistant from the distal end of the catheter. A wire passes throughthe first channel, out of the first channel via the first lateralopening, into the second channel via the second lateral opening, andthrough the second channel. The wire is deployed, i.e., pushed out ofthe catheter, such that the deployed portion of the wire is loop-shaped.The wire facilitates finding the fossa ovalis, and/or stabilizing thecatheter as the fossa ovalis is punctured.

Applications of the present invention also include a catheter that has awall having both a braided portion and an unbraided portion. Areinforcing tube at least partially surrounds the unbraided portion ofthe catheter wall. A control handle surrounds the catheter such that (a)all of the catheter wall that is distal to a distal end of the controlhandle comprises the braided portion, and (b) at least 10% of thecatheter wall that is proximal to the distal end of the control handlecomprises the unbraided portion.

Applications of the present invention also include various types ofhollow needles having flexible distal portions.

In general, apparatus and methods described herein can also be used topenetrate other body orifices. (In this context, penetration of the bodyorifice might not include puncturing with a puncturing element, as istypically the case for the fossa ovalis.) For example, apparatus andmethods described herein can be used to pass a catheter and/or atherapeutic device through the coronary sinus ostium and into thecoronary sinus. Furthermore, apparatus and methods described herein canalso be used to locate an opening, natural or manmade, in a portion ofanatomy. For example, apparatus and methods described herein can be usedto locate the coronary sinus ostium, a natural opening in the fossaovalis, or a puncture in the fossa ovalis. In some applications,apparatus described herein may be further configured to deliver a plug(e.g., an Amplatzer™), or other such stopping device, to the opening.

There is therefore provided, in accordance with some applications of thepresent invention, apparatus including:

-   -   a catheter shaped to define a catheter lumen,        -   a wall of which catheter (a) comprising a braided portion            having an outer surface, an inner surface, and a braided            interior between the outer and inner surfaces, and (b) being            shaped to define a first longitudinally-running channel            therethrough and a second longitudinally-running channel            therethrough, and        -   a distal portion of which catheter being shaped to define a            first lateral opening and a second lateral opening, an angle            between (a) a first line running between the first and            second lateral openings, and (b) a second line that is            parallel to a central longitudinal axis of the catheter when            the catheter is straight, being between 30 and 150 degrees;            and

a flexible longitudinal member that passes (a) from a proximal portionof the catheter to the distal portion of the catheter via the firstchannel, (b) out of the first channel via the first lateral opening, (c)into the second channel via the second lateral opening, and (d) from thedistal portion of the catheter to the proximal portion of the cathetervia the second channel.

In some applications, the angle between the first and second lines isbetween 60 and 120 degrees. In some applications, the angle between thefirst and second lines is between 80 and 100 degrees.

In some applications, the first and second openings are separated fromone another by an angle of 170-190 degrees measured along acircumference of the catheter.

In some applications, the apparatus further includes a needle shaped tobe slidably disposed within the catheter lumen.

In some applications, the apparatus further includes:

a dilator element shaped to be slidably disposed within the catheterlumen, the dilator element being shaped to define a dilator lumen; and

a dilator tip disposed at a distal end of the dilator element, thedilator tip being configured to dilate an opening created by the needle.

In sonic applications, the needle is shaped to be slidably disposedwithin the dilator lumen.

For sonic applications, the needle is hollow, and includes (a) aproximal portion, and (b) a helical distal portion, and the apparatusfurther includes a fluid-impermeable cover surrounding the helicaldistal portion of the needle.

For some applications, the needle is hollow, and includes (a) a proximalportion, and (h) a distal portion that is more flexible than theproximal portion, and the apparatus further includes a fluid-impermeablecover surrounding the distal portion of the needle.

For some applications, the needle is hollow, and includes (a) a proximalportion, and (b) a distal portion including a wall that is shaped todefine a plurality of openings that pass completely therethrough, andthe apparatus further includes a fluid-impermeable cover surrounding thedistal portion of the needle.

For some applications, the needle is hollow, and includes (a) a proximalportion, and (b) a distal portion including an elastomeric tube havingan outer surface, an inner surface, and an interior portion between theouter and inner surfaces that is selected from the group consisting of:a braided metal interior, and a coiled metal interior.

For some applications, the needle is hollow, and includes:

a proximal portion having an outer diameter between 0.7 and 3 mm, alength between 650 and 1200 mm, and a wall thickness between 0.1 and 0.3mm; and

a distal portion at least partially made of nitinol, the distal portionhaving an outer diameter between (15 and 1.5 mm and a length between 30and 200 mm.

For some applications, the needle is electrically conductive, andwherein the apparatus further includes:

one or more conductors; and

a controller, which is coupled to the needle by the conductors, andwhich is configured to drive the needle to apply energy capable ofcreating a hole through tissue.

In some applications, the flexible longitudinal member is mechanicallyresilient.

In some applications, a diameter of the flexible longitudinal member isbetween 0.1 and 0.5 mm.

In some applications, the flexible longitudinal member includes a wire.

In some applications, the flexible longitudinal member includes amaterial selected from the group consisting of: nitinol, stainlesssteel, and chromium cobalt.

In some applications, the flexible longitudinal member is configured tobe deployed such that, in an absence of any force applied to thedeployed portion of the flexible longitudinal member by an element thatis not part of the apparatus, a deployment angle of the flexiblelongitudinal member is between 10 and 80 degrees,

the deployment angle being an angle between (a) a vector that is (i)tangent to the flexible longitudinal member at an exit point of theflexible longitudinal member from the catheter, and (ii) directed awayfrom the catheter, and (b) a distally-directed vector that is parallelto a longitudinal axis of the catheter at the exit point.

In some applications, the flexible longitudinal member is configured tobe deployed such that, in the absence of any force applied to thedeployed portion of the flexible longitudinal member by an element thatis not part of the apparatus, the deployment angle is between 30 and 60degrees.

In some applications, the flexible longitudinal member is radiopaque.

In some applications, the apparatus further includes a plurality ofradiopaque markers coupled to the flexible longitudinal member.

There is further provided, in accordance with some applications of thepresent invention, apparatus including:

-   -   a catheter having a catheter wall that comprises:        -   a braided portion having an outer surface, an inner surface,            and a braided interior between the outer and inner surfaces;            and        -   an unbraided portion having an unbraided interior;

a control element shaped to surround a proximal portion of the cathetersuch that (a) all of the catheter wall that is distal to a distal end ofthe control element comprises the braided portion, and (b) at least 10%of the catheter wall that is proximal to the distal end of the controlelement comprises the unbraided portion; and

a reinforcing tube at least partially surrounding the unbraided portion.

In some applications,

a wall of the reinforcing tube is shaped to define one or more lateralopenings therethrough,

the catheter wall is shaped to define one or more longitudinally-runningchannels therethrough, and

the apparatus further comprises one or more flexible longitudinalmembers passing through the lateral openings and through thelongitudinally-running channels.

In some applications, the flexible longitudinal members are coupled tothe control element.

In some applications, a length of the braided portion is between 600 and1000 mm.

In some applications, a length of the unbraided portion is between 250and 400 mm.

There is further provided, in accordance with some applications of thepresent invention, apparatus including:

-   -   a hollow needle comprising:        -   a proximal portion having an outer diameter between 0.7 and            3 mm, a length between 650 and 1200 mm, and a wall thickness            between 0.1 and 0.3 mm; and        -   a helical distal portion having an outer diameter between            0.5 and 1.5 mm and a length between 50 and 200 mm; and    -   a fluid-impermeable cover surrounding the helical distal portion        of the needle.

There is further provided, in accordance with some applications of thepresent invention, apparatus including:

-   -   a hollow needle comprising:        -   a proximal portion having an outer diameter between 0.7 and            3 mm, a length between 650 and 1200 mm, and a wall thickness            between 0.1 and 0.3 mm; and        -   a laser-cut distal portion having an outer diameter between            0.5 and 1.5 mm and a length between 50 and 200 mm; and    -   a fluid-impermeable cover surrounding the laser-cut distal        portion of the needle.

There is further provided, in accordance with some applications of thepresent invention, apparatus including:

-   -   a hollow needle comprising:        -   a proximal portion having an outer diameter between 0.7 and            3 mm, a length between 650 and 1200 mm, and a wall thickness            between 0.1 and 0.3 mm; and        -   a distal portion (a) having an outer diameter between 0.5            and 1.5 mm and a length between 50 and 200 mm, and (b)            comprising a wall that is shaped to define a plurality of            openings that pass completely therethrough; and    -   a fluid-impermeable cover surrounding the laser-cut distal        portion of the needle.

In some applications, the wall of the distal portion of the hollowneedle is shaped to define a plurality of slits therethrough.

There is further provided, in accordance with some applications of thepresent invention, apparatus including:

-   -   a hollow needle comprising:        -   a proximal portion having an outer diameter between 0.7 and            3 mm, a length between 650 and 1200 mm, and a wall thickness            between 0.1 and 0.3 mm; and        -   a distal portion comprising an elastomeric tube having an            outer surface, an inner surface, and an interior portion            between the outer and inner surfaces that is selected from            the group consisting of: a braided metal interior, and a            coiled metal interior,        -   the distal portion having an outer diameter between 0.5 and            1.5 mm and a length between 50 and 200 mm.

There is further provided, in accordance with some applications of thepresent invention, apparatus including:

-   -   a hollow needle comprising:        -   a proximal portion having an outer diameter between 0,7 and            3 mm, a length between 650 and 1200 mm, and a wall thickness            between 0.1 and 0.3 mm; and        -   a distal portion at least partially made of nitinol, the            distal portion having an outer diameter between 0.5 and 1.5            mm and a length between 50 and 200 mm.

There is further provided, in accordance with some applications of thepresent invention, a method for puncturing a fossa ovalis of a heart,the method including:

inserting a catheter into a right atrium the heart;

advancing distal portion of the catheter toward the fossa ovalis;

deploying a flexible longitudinal member and a needle from the catheter,such that (a) a deployed portion of the flexible longitudinal member isloop-shaped, and (b) the needle is on a first side of the deployedportion of the flexible longitudinal member;

contacting the fossa ovalis with the deployed portion of the flexiblelongitudinal member;

passing a distal end of the needle through the deployed portion of theflexible longitudinal member to a second side of the deployed portion ofthe flexible longitudinal member that is opposite the first side, andpuncturing the fossa ovalis with the needle; and

while the distal end of the needle is on the second side of the deployedportion of the flexible longitudinal member, withdrawing the deployedportion of the flexible longitudinal member toward the catheter.

In some applications, contacting the fossa ovalis with the deployedportion of the flexible longitudinal member includes contacting an innerperimeter of the fossa ovalis.

In some applications, the method further includes, before contacting thefossa ovalis with the deployed portion of the flexible longitudinalmember, moving the deployed portion of the flexible longitudinal memberalong a surface of an interatrial septum of the heart, until theflexible longitudinal member contacts the fossa ovalis.

In some applications, moving the deployed portion of the flexiblelongitudinal member along the surface of the interatrial septum includesmoving the deployed portion of the flexible longitudinal member towardthe fossa ovalis from below the fossa ovalis.

In some applications, deploying the flexible longitudinal memberincludes deploying the flexible longitudinal member such that adeployment angle of the flexible longitudinal member is between 10 and80 degrees,

the deployment angle being an angle between (a) a vector that is (i)tangent to the flexible longitudinal member at an exit point of theflexible longitudinal member from the catheter, and (ii) directed awayfrom the catheter, and (b) a distally-directed vector that is parallelto a longitudinal axis of the catheter at the exit point.

In some applications, deploying the flexible longitudinal memberincludes deploying the flexible longitudinal member such that thedeployment angle is between 30 and 60 degrees.

In some applications, deploying the flexible longitudinal member fromthe catheter includes passing the flexible longitudinal member throughtwo lateral openings at a distal portion of the catheter.

In some applications, the flexible longitudinal member is radiopaque,and the method further includes using fluoroscopic imaging to view theflexible longitudinal member during and after deployment thereof.

In some applications, the method further includes, before puncturing thefossa ovalis, flexing a distal portion of the needle by steering thecatheter.

In some applications, the catheter is a puncture-tool catheter, andinserting the puncture-tool catheter into the right atrium includes:

inserting a delivery catheter of a left-side therapeutic delivery systeminto the right atrium; and

advancing the puncture-tool catheter through the delivery catheter intothe right atrium.

There is further provided, in accordance with some applications of thepresent invention, a method for puncturing a fossa ovalis of a heart,the method including:

inserting a catheter into a right atrium of the heart;

advancing the catheter toward an interatrial septum of the heart;

subsequently, inserting a needle into a lumen of the catheter;

flexing a distal portion of the needle by steering the catheter; and

following the flexing of the distal portion of the needle, using theneedle to puncture the fossa ovalis.

In some applications, the catheter is a puncture-tool catheter, andinserting the puncture-tool catheter into the right atrium includes:

inserting a delivery catheter of a left-side therapeutic delivery systeminto the right atrium; and

advancing the puncture-tool catheter through the delivery catheter intothe right atrium.

There is further provided, in accordance with some applications of thepresent invention, apparatus including:

-   -   a hollow needle including:        -   a proximal portion; and        -   a helical distal portion; and    -   a fluid-impermeable cover surrounding the helical distal portion        of the needle.

In some applications, the fluid-impermeable cover fits snugly around thehelical distal portion of the needle.

In sonic applications, the proximal portion has an outer diameterbetween 0.7 and 3 mm.

In some applications, the proximal portion has a length between 650 and1200 mm.

In some applications, the proximal portion has a wall thickness between0.1 and 0.3 mm.

In some applications, the distal portion has an outer diameter between0.5 and 1.5 mm.

In some applications, the distal portion has a length between 30 and 200mm.

In some applications, the distal portion has a length between 30 and 100mm.

In some applications, the helical distal portion includes ahelically-cut tube.

In some applications, the helical distal portion includes one or morecoiled wires.

There is further provided, in accordance with some applications of thepresent invention, apparatus including:

-   -   a hollow needle including:        -   a proximal portion; and        -   a distal portion that is more flexible than the proximal            portion; and    -   a fluid-impermeable cover surrounding the distal portion of the        needle.

In some applications, the distal portion includes a wall that is cut atone or more locations between longitudinal ends of the wall.

There is further provided, in accordance with some applications of thepresent invention, apparatus including:

-   -   a hollow needle including:        -   a proximal portion; and        -   a distal portion including a wall that is shaped to define a            plurality of openings that pass completely therethrough; and    -   a fluid-impermeable cover surrounding the distal portion of the        needle.

In some applications, the wall of the distal portion of the hollowneedle is shaped to define 25-250 openings.

In some applications, the wall of the distal portion of the hollowneedle is shaped to define a plurality of slits therethrough.

There is further provided, in accordance with some applications of thepresent invention, apparatus including:

-   -   a hollow needle including:        -   a proximal portion; and        -   a distal portion including an elastomeric tube having an            outer surface, an inner surface, and an interior portion            between the outer and inner surfaces that is selected from            the group consisting of: a braided metal interior, and a            coiled metal interior.

There is further provided, in accordance with some applications of thepresent invention, apparatus including:

-   -   a hollow needle including:        -   a proximal portion having an outer diameter between 0.7 and            3 mm, a length between 650 and 1200 mm, and a wall thickness            between 0.1 and 0.3 mm; and        -   a distal portion at least partially made of nitinol, the            distal portion having an outer diameter between 0.5 and 1.5            mm and a length between 30 and 200 mm.

There is further provided, in accordance with some applications of thepresent invention, apparatus including:

-   -   a tube shaped to define a tube lumen, a reduced-diameter portion        of the tube lumen that is between 5 and 30 mm of a distal end of        the tube having a diameter that is reduced, relative to a        portion of the tube lumen that is proximal to the        reduced-diameter portion; and    -   a hollow needle, including:        -   a proximal portion;        -   a distal portion that is more flexible than the proximal            portion;        -   a distal-most end portion that is distal to the distal            portion and is less flexible than the distal portion, the            distal-most end portion including an increased-diameter            portion having a diameter that is greater than another part            of the distal-most end portion,    -   the diameter of the reduced-diameter portion of the tube lumen        being (a) less than an outer diameter of the increased-diameter        portion, and (b) greater than an outer diameter of the other        part of the distal-most end portion.

In some applications, the distal-most end portion has a length between10 and 30 mm.

In some applications, the increased-diameter portion is disposed at aproximal end of the distal-most end portion.

In some applications, the outer diameter of the increased-diameterportion is greater than an outer diameter of the distal portion.

The present invention will be more fully understood from the followingdetailed description of applications thereof, taken together with thedrawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-D are schematic illustrations of apparatus for puncturing afossa ovalis of a subject, in accordance with some applications of thepresent invention;

FIGS. 2A-B are schematic illustrations of a cross-section of a wall of acatheter, in accordance with some applications of the present invention;

FIG. 3 is a schematic illustration of a catheter, in accordance withsome applications of the present invention;

FIG. 4 is a schematic illustration of a method for puncturing the fossaovalis, in accordance with some applications of the present invention;

FIGS. 5-6 are schematic illustrations of a catheter, in accordance withsome applications of the present invention;

FIGS. 7-10 are schematic illustrations of hollow needles having flexibledistal portions, in accordance with some applications of the presentinvention;

FIG. 11 is a schematic illustration of apparatus used, for example, forfossa ovalis penetration, in accordance with some applications of thepresent invention;

FIG. 12 is a schematic illustration of the use of the apparatusdescribed herein in combination with a left-side therapeutic deliverysystem, in accordance with an application of the present invention; and

FIG. 13 is a schematic illustration of a configuration of the apparatusdescribed herein, in accordance with an application of the presentinvention.

DETAILED DESCRIPTION OF APPLICATIONS

Reference is now made to FIGS. 1A-D, which are schematic illustrationsof apparatus 34 for puncturing a fossa ovalis 18 of a subject, and amethod of using apparatus 34, in accordance with some applications ofthe present invention. Apparatus 34 comprises a catheter 38, which mayalso be referred to by those in the field as an introducer tube.Catheter 38 is shaped to define a catheter lumen 52.

Reference is also made to FIGS. 2A-B, which are schematic illustrationsof a cross-section of a wall 39 of catheter 38, in accordance with someapplications of the present invention. Wall 39 comprises a braidedportion 41 (shown in FIG. 2A), which has an outer surface 45, an innersurface 47, and a braided interior 53 between outer surface 45 and innersurface 47. Wall 39 also comprises an unbraided portion 43 (shown incross-section in FIG. 2B), which is typically disposed proximally tobraided portion 41. (Braided portion 41 and unbraided portion 43 aredescribed in more detail hereinbelow with reference to FIGS. 5-6.) Wall39 is shaped to define a first longitudinally-running channel 27 a and asecond longitudinally-running channel 27 b therethrough. (Channels 27 aand 27 b run through both the braided and unbraided portions.) A distalportion of catheter 38 is shaped to define a first lateral opening 26 aand a second lateral opening 26 b (shown in FIG. 1A). A flexiblelongitudinal member 14 (e.g., a wire) passes (a) from a proximal portionof the catheter to the distal portion of the catheter via first channel27 a, (b) out of first channel 27 a via first lateral opening 26 a, (c)into second channel 27 b via second lateral opening 26 b, and (d) fromthe distal portion of the catheter to the proximal portion of thecatheter via second channel 27 b.

Typically, flexible longitudinal member 14 is mechanically resilient,i.e., it does not readily buckle upon being subjected to a compressiveforce, as would, for example, a string. The flexible longitudinal membertypically comprises nitinol, stainless steel, and/or chromium cobalt,and typically has a diameter D that is at least 0.1 mm and/or less than0.5 mm.

Catheter 38 is typically inserted into a vein in the pelvic area of thesubject (e.g., the femoral vein), advanced toward the heart through theinferior vena cava, and inserted into the right atrium of the subject'sheart. (Typically, catheter 38 is contained within the lumen of a sheathduring parts of the insertion and/or withdrawal of the catheter, such asto reduce the risk of damage to surrounding tissue.) Following theinsertion into the right atrium, the distal portion of catheter 38 isadvanced toward interatrial septum 72 of the heart (FIG. 1A).Subsequently, as shown in FIG. 1B, the following two steps are performedsequentially (in either order), or simultaneously:

(a) A needle 32 is inserted into catheter lumen 52. Needle 32 is shapedto be slidably disposed within the catheter lumen. Typically, a dilatorelement 49 shaped so as to define a dilator lumen is shaped to beslidably disposed within the catheter lumen, and the needle is shaped tobe slidably disposed within the dilator lumen. The needle is insertedinto the dilator lumen, and is advanced up to a tip 16 of the dilatorelement. (Although dilator element 49 may also be embodied as acatheter, the present description refers exclusively to catheter 38—the“introducer tube”—as a catheter.)

(b) Flexible longitudinal member 14 is deployed from the catheter, suchthat (i) a deployed portion of the flexible longitudinal member isloop-shaped, and (ii) the needle is on a first side of the deployedportion of the flexible longitudinal member. Typically, the flexiblelongitudinal member is deployed such that a deployment angle theta ofthe flexible longitudinal member is at least 10 degrees and/or less than80 degrees, e.g., between 30 and 60 degrees. Deployment angle theta isdefined as the angle between (a) a vector 64 that is tangent to theflexible longitudinal member at an exit point 68 of the flexiblelongitudinal member, and is directed away from the catheter, and (b) adistally-directed vector 66 that is parallel to the longitudinal axis 70of the catheter at exit point 68. (Exit point 68 is identical to one ofopenings 26 a and 26 b.) As described hereinabove, the flexiblelongitudinal member is deployed by passing the flexible longitudinalmember through openings 26 a and 26 b.

The catheter is steered until fossa ovalis 18 (e.g., an inner perimeterof the fossa ovalis) is contacted with the deployed portion of theflexible longitudinal member, as shown in FIG. 1B. Following thecontacting, needle 32 is deployed, typically while within dilatorelement 49, as shown in the figure. Further typically, as shown in FIG.1C, dilator tip 16 is brought into contact with the fossa ovalis. Theneedle is then advanced through a distal opening of the dilator tip andthrough the fossa ovalis, thus puncturing a hole in the fossa ovalis.Dilator tip 16 then dilates an opening created by the needle.

As shown in FIG. 1B, prior to puncturing the fossa ovalis, the distalend of needle 32 is typically passed through the deployed portion of theflexible longitudinal member to a second side of the deployed portion ofthe flexible longitudinal member that is opposite the first side. (Thedistal end of the needle is typically passed through the loop whiledisposed inside of the dilator element.) Subsequently, while the distalend of the needle is on the second side of the deployed portion of theflexible longitudinal member, the deployed portion of the flexiblelongitudinal member is withdrawn toward the catheter (FIG. 1D).

Typically, catheter 38 is flexibly and/or rotatably steerable viacontrol wires 80 running through control-wire channels 20. Thesteerability of catheter 38 facilitates better localization of thedesired puncturing point. Furthermore, a distal flexible portion of theneedle (described hereinbelow with reference to FIGS. 7-10), while it isinside the catheter lumen, may be flexed by steering the catheter.Following the flexing of the distal portion of the needle, the needle isused to puncture the fossa ovalis. The flexing of the needle facilitatesthe puncturing of the fossa ovalis at the desired location, and/or atthe desired angle of the needle relative to the fossa ovalis.Furthermore, owing to the flexibility of the needle, there is generallyno need to bend the needle prior to insertion of the needle into thesubject; rather, the needle may be advanced toward the heart of thesubject while in a generally straight position. A straight position isgenerally preferred over a bent position, in that it provides for lessdistortion of the vein (e.g., the femoral vein) through which the needleis advanced.

Reference is now made to FIG. 3, which is a schematic illustration ofcatheter 38, in accordance with some applications of the presentinvention. Typically, first and second openings 26 a and 26 b aredisposed at substantially the same distance from the distal end of thecatheter. An advantage of this disposition is that the loop may bedeployed in a forward-facing direction, rather than laterally. Forexample, an angle alpha between (a) a first line 76 running between thefirst and second lateral openings, and (b) a second line 78 that isparallel to a central longitudinal axis of the catheter when thecatheter is straight, may be at least 30 and/or less than 150 degrees,e.g., between 60 and 120 degrees, e.g., between 80 and 100 degrees. (Anangle alpha of 90 degrees implies that the first and second openings aredisposed at the same distance from the distal end of the catheter.)Alternatively or additionally, the distance of one opening from thedistal end of the catheter differs by less than 1 cm from the distanceof the other opening.

Further typically, the first and second openings are separated from oneanother by an angle beta of at least 170 degrees and/or less than 190degrees (e.g., 180 degrees) measured along a circumference of thecatheter. Thus, when the flexible longitudinal member is in itswithdrawn position, it “occupies” only 170-190 degrees around theoutside surface of the catheter, both prior to deployment and followingwithdrawal. In contrast, if beta were farther away from 180 degrees, thewithdrawn flexible longitudinal member might occupy a relatively largeangle, either prior to deployment or following withdrawal. For example,if beta were 90 degrees, the flexible longitudinal member wouldtypically occupy 270 degrees either prior to deployment or followingwithdrawal, if, as described hereinabove with reference to FIG. 1D, thedeployment and withdrawal of the flexible longitudinal member are donefrom/toward opposite sides of the catheter. It is typically preferredthat such a large portion of the flexible longitudinal member not bedisposed outside of the catheter when the flexible longitudinal memberis in its withdrawn position, since the risk of collateral damage totissue typically increases as more of the flexible longitudinal memberis exposed. The angle beta of 170-190 degrees is thus advantageous,particularly when the deployment and withdrawal are done from/toopposite sides of the catheter. (It is noted that for some procedures orfor some patients, an angle beta outside of 170-190 degrees isappropriate.)

Reference is now made to FIG. 4, which is a schematic illustration of amethod for puncturing the fossa ovalis, in accordance with someapplications of the present invention. Before contacting the fossaovalis with the deployed portion of flexible longitudinal member 14, thedeployed portion of the flexible longitudinal member is moved along asurface of interatrial septum 72, until the flexible longitudinal membercontacts the fossa ovalis. In some applications, as shown in FIG. 4, thedeployed portion of the flexible longitudinal member is moved toward thefossa ovalis from below the fossa ovalis. In some applications, theflexible longitudinal member is radiopaque and/or is coupled to aplurality of radiopaque markers. In such applications, fluoroscopicimaging is used to view the flexible longitudinal member during andafter deployment thereof. For example, fluoroscopic imaging may be usedto view the flexible longitudinal member as it is moved toward the fossaovalis, in order to help identify when the flexible longitudinal memberhas reached the fossa ovalis.

Reference is now made to FIGS. 5-6, which are schematic illustrations ofcatheter 38, in accordance with some applications of the presentinvention. FIG. 5 shows a control element 30 (e.g., a control handle)shaped to surround a proximal portion of catheter 38. Control element 30facilitates the steering of the catheter, as well as control of needle32 and/or of flexible longitudinal member 14. As described hereinabovewith reference to FIGS. 2A-B, wall 39 of catheter 38 typically comprisesbraided portion 41 and unbraided portion 43. Typically, control element30 surrounds the catheter such that (a) all of the catheter wall that isdistal to a distal end of the control element comprises braided portion41, and (b) at least 10% of the catheter wall that is proximal to thedistal end of the control element comprises unbraided portion 43.Typically, a length L1 of the braided portion is between 600 and 1000mm, and/or a length L2 of the unbraided portion is between 250 and 400mm.

Typically, a braided wall is preferred to an unbraided wall, in that thebraiding reduces the buckling of the catheter when a pushing force isapplied. However, some manufacturing processes limit the number oflateral openings that can be made through a braided wall; thus, in orderto allow for the proximal lateral openings 84 shown in FIG. 6, it may benecessary, when using such manufacturing processes, to make the proximalportion of the catheter wall unbraided. Some applications of the presentinvention compensate for the use of an unbraided wall, by including areinforcing tube 82 that at least partially surrounds the unbraidedportion of the catheter wall. Reinforcing tube 82 provides stability tothe catheter, in lieu of the braiding.

As shown in FIG. 6, a wall of the reinforcing tube is typically shapedto define one or more lateral openings 84 therethrough. (Openings 84 arealigned with lateral openings in the catheter wall.) Control wires 80,and/or flexible longitudinal member 14, pass through openings 84 intochannels 20, 27 a, and 27 b, shown in FIGS. 2A-B. Control element 30 iscoupled to control wires 80, and/or to flexible longitudinal member 14.

Reference is now made to FIGS. 7-10, which are schematic illustrationsof a hollow needle 86 having a flexible distal portion 88, in accordancewith some applications of the present invention. The applications shownin FIGS. 7-10 are similar to each other in function; they differ fromeach other mainly in the structure of flexible distal portion 88. Needle86 may be used as needle 32 in apparatus 34 (FIGS. 1A-D). An advantageof needle 86 is that flexible distal portion 88 of the needle is moreflexible than other portions of the needle (e.g., than a proximalportion 90 of the needle), such that, flexible distal portion 88, whileinside the catheter lumen, may be flexed by steering the catheter.

Needle 86 comprises proximal portion 90, which generally runs throughmost of the length of the catheter, and which is used to transferpushing force to the distal portion of the needle. Proximal portion 90typically has an outer diameter D1 that is at least 0.7 mm and/or lessthan 3 mm, and/or a length L3 that is at least 650 mm and/or less than1200 mm, and/or a wall thickness t1 that is at least 0.1 mm and/or lessthan 0.3 mm. Flexible distal portion 88 typically has an outer diameterD2 that is at least 0.5 mm and/or less than 1.5 mm, and/or a length L4that is at least 30 mm and/or less than 200 mm, e.g., between 30 and 100mm. Needle 86 also comprises a distal-most end portion 94, which is lessflexible than flexible distal portion 88, and is typically relativelyrigid. (The relative rigidity of distal-most end portion 94 facilitatesthe puncturing function of the needle.) In some applications, thedistal-most end portion comprises an increased-diameter portion 104having a diameter that is greater than the other part of the distal-mostend portion. Increased-diameter portion 104 is typically disposed at theproximal end of the distal-most end portion. The function of theincreased-diameter portion is described below, with reference to FIG.11.

In FIG. 7, flexible distal portion 88 of the needle comprises anelastomeric tube 96 having an outer surface 97, an inner surface 99, anda braided and/or coiled metal interior 98 between the inner and outersurfaces. (Thus flexible distal portion 88 may be structurally similarto the braided portion of the catheter, shown in FIG. 2A.) Elastomerictube 96 provides flexibility to flexible distal portion 88. Braidedand/or coiled metal interior 98 reinforces the elastomeric tube suchthat it is less susceptible to buckling, and also facilitates thetransfer of electric current between the distal and proximal ends of theneedle. The transfer of electric current may be used to verify that theneedle has punctured the fossa ovalis, and/or apply an ablating current,e.g., a radiofrequency (RF) current, or other energy to puncture thefossa ovalis, such as described hereinbelow with reference to FIG. 13.

The applications of FIGS. 8-9 are similar to that of FIG. 7 in that (a)the dimensions of flexible distal portion 88 and proximal portion 90 aregenerally as described above, and (b) flexible distal portion 88 is moreflexible than other portions of the needle. (The applications of FIGS.8-9 also provide for the transfer of electric current via flexibledistal portion 88.) The applications of FIGS. 8-9 differ from that ofFIG. 7 in that the flexibility of the distal portion is facilitated bythe helical configuration of the distal portion, rather than byelastomeric tube 96. The helical configuration of the distal portion maybe achieved, for example, by cutting (e.g., laser-cutting) a tube (e.g.,a metallic tube), as in FIG. 8, or by coiling one or more wires (e.g.,metallic wires), as in FIG. 9.

The application of FIG. 10 is similar to those of FIGS. 8-9 in that (a)the dimensions of flexible distal portion 88 and proximal portion 90 aregenerally as described above, and (b) flexible distal portion 88 is moreflexible than other portions of the needle. Furthermore, the applicationof FIG. 10 is similar to that of FIG. 8 in that the respectiveconfigurations of the distal portions may be achieved via cutting (e.g.,laser-cutting) a tube wall at one or more locations between longitudinalends of the wall. (The application of FIG. 10 also provides for thetransfer of electric current via flexible distal portion 88.) Theapplication of FIG. 10 differs from those of FIGS. 8-9 in that theflexibility of the distal portion is facilitated by the wall of thedistal portion being shaped to define a plurality of openings 102 (e.g.,slits) that pass completely therethrough. Typically, the number ofopenings 102 is at least 25 and/or less than 250.

For the applications of FIGS. 8-10, in order to keep the lumen of theneedle fluidly isolated from the needle's environment, afluid-impermeable cover 100 (e.g., a polymer film) surrounds (e.g., fitssnugly around) the distal portion of the needle. (Also typically, thedistal portion is internally lined by a lining such as a polymer film.)By keeping the lumen of the needle fluidly isolated, fluid-impermeablecover 100 facilitates measurement, using a pressure sensor disposed atthe proximal end of the needle, of the pressure at the distal tip of theneedle. (Elastomeric tube 96, shown in FIG. 7, is alsofluid-impermeable, and also facilitates pressure measurements.)

In general, flexible distal portion 88 may include various combinationsor subcombinations of elements from FIGS. 7-10. Furthermore, in someapplications, flexible distal portion 88 comprises a portion that is atleast partially made of nitinol; for example, braided and/or coiledmetal interior 98 (FIG. 7) may be at least partially made of nitinol.The nitinol provides flexibility to flexible distal portion 88, whilealso facilitating the transfer of electric current. Similarly,distal-most end portion 94 and/or proximal portion 90 may be at leastpartially made of nitinol. Typically, portions of the flexible needlesof FIGS. 7-10 include stainless steel and/or another metal such astitanium, alternatively or additionally to nitinol.

Reference is now made to FIG. 11, which is a schematic illustration ofapparatus 106 used, for example, for fossa ovalis penetration, inaccordance with some applications of the present invention. Apparatus106 includes a tube, such as dilator element 49, shaped to define a tubelumen 108. A reduced-diameter portion 110 of the tube lumen is locatedat a distance d from the distal end of the tube, d being at least 5 mmand/or less than 30 mm. Reduced-diameter portion 110, which may includea protrusion and/or a narrowing of the tube lumen, has a diameter D3that is reduced, relative to a portion of the tube lumen that isproximal to the reduced-diameter portion. For example, in FIG. 11, theportion of the tube lumen that is proximal to the reduced-diameterportion has a diameter D4 that is greater than D3.

Apparatus 106 also includes hollow needle 86, described hereinabove withreference to FIGS. 7-10. Diameter D3 of the reduced-diameter portion ofthe tube lumen is less than the outer diameter D5 of increased-diameterportion 104 of the distal-most end portion of the needle, but is greaterthan the outer diameter D6 of the other part of the distal-most endportion. Hence, only the part of the distal-most end portion that isdistal to the increased-diameter portion advances past thereduced-diameter portion of the tube lumen. (Typically, diameter D5 isalso greater than outer diameter D2 of flexible distal portion 88.)

In some applications, distal-most end portion 94 has a length L that isat least 10 mm and/or less than 30 mm. In some applications, theincreased-diameter portion is formed by attaching a ring to part of thedistal-most end portion of the needle. The ring is attached at adistance from the distal tip of the needle that corresponds to thedesired amount of protrusion of the needle. (Typically, the ring ispermanently attached.) In other applications, the distal-most endportion of the needle is shaped during manufacture to define theincreased-diameter portion.

Reference is made to FIGS. 7-11. It is noted that the use of hollowneedle 86 may be particularly advantageous when flexible longitudinalmember 14 (or other fossa-ovalis-locating-facilitating apparatus, suchas those described in US 2014/0309675 to Maisano, which is incorporatedherein by reference) is deployed from the catheter. Flexiblelongitudinal member 14 provides a “buffer” between the catheter andseptum (see FIG. 1B), allowing the catheter to be steered withoutsignificant risk of accidentally puncturing the septum. In other words,without flexible longitudinal member 14, it might not be practical tosteer the catheter, even if the needle were to have a flexible distalportion. Thus there is a particular synergy that is obtained whenflexible longitudinal member 14 is used together with hollow needle 86.

Reference is made to FIG. 12, which is a schematic illustration of theuse of apparatus 34 in combination with a left-side therapeutic deliverysystem, in accordance with an application of the present invention. Thistechnique may be practiced in combination with any of the techniquesdescribed herein. In this application, a delivery catheter 120 of aleft-side therapeutic delivery system is first inserted into the rightatrium, using techniques known in the art. Apparatus 34, includingcatheter 38 thereof, is advanced through delivery catheter 120 into theright atrium, and is then used to puncture fossa ovalis 18 or anothersite on interatrial septum 72, using techniques described herein.Thereafter, apparatus 34 is withdrawn from the body through deliverycatheter 120, leaving delivery catheter 120 in the heart. Deliverycatheter 120 is used to introduce a left-side therapeutic device, suchas a valve repair or replacement device or a left atrial appendageimplant.

Typically, an outer diameter of delivery catheter 120 equals at least150% of an outer diameter of catheter 38, such as at least 200%. Forexample, the outer diameter of delivery catheter 120 may be between 20and 30 Fr, and the outer diameter of catheter 38 may be between 12 and14 Fr.

For some applications, before withdrawal of apparatus 34 from the body,delivery catheter 120 is advanced over dilator element 49 while thedilator element is disposed within the hole in fossa ovalis 18 or theother site on interatrial septum 72, until a distal end opening ofdelivery catheter 120 is disposed in the left atrium. After withdrawalof apparatus 34 from the body, delivery catheter 120 is used tointroduce the left-side therapeutic device into the left atrium.

Reference is made to FIG. 13, which is a schematic illustration of aconfiguration of apparatus 34, in accordance with an application of thepresent invention. This technique may be practiced in combination withany of the techniques described herein. In this application, needle 32is electrically conductive, and is coupled by one or more conductors 178to a controller 180, which comprises or is in electrical communicationwith an energy source. The controller is configured to drive needle 32to apply an ablating current, e.g., an RF current, to puncture the fossaovalis or interatrial septum 72. Alternatively, instead of using anablating current, other energy may be applied, such as heat, ultrasound,or light (e.g., laser) energy. The energy-based puncturing may beperformed instead of or in combination with the force-based mechanicalpuncturing by the needle. For some applications, the distal tip of theneedle is blunt.

In general, apparatus described herein may be used, and techniquesdescribed herein may be practiced, in combination with apparatus andtechniques described in the following patent applications, all of whichare incorporated herein by reference:

-   -   U.S. application Ser. No. 14/245,135, filed Apr. 4, 2014, which        published as US Patent Application Publication 2014/0309675;    -   International Application PCT/IL2014/050338, filed Apr. 7, 2014,        which published as PCT Publication WO 2014/170890;    -   U.S. application Ser. No. 14/287,470, filed May 27, 2014, which        published as US Patent Application Publication 2014/0309678;    -   U.S. application Ser. No. 14/287,523, filed May 27, 2014, which        published as US Patent Application Publication 2014/0309679;    -   U.S. application Ser. No. 14/513,435 to Sapir et al, which        published as U.S. Patent Application Publication 2016/0100859;        and    -   U.S. Provisional Application 62/095,150, filed Dec. 22, 2014.

It will be appreciated by persons skilled in the art that the presentinvention is not limited to what has been particularly shown anddescribed hereinabove. Rather, the scope of the present inventionincludes both combinations and subcombinations of the various featuresdescribed hereinabove, as well as variations and modifications thereofthat are not in the prior art, which would occur to persons skilled inthe art upon reading the foregoing description.

The invention claimed is:
 1. Apparatus comprising: a catheter shaped todefine a catheter lumen, wherein a wall of the catheter (a) comprises abraided portion, and (b) is shaped to define a firstlongitudinally-running channel through the wall and a secondlongitudinally-running channel through the wall, and wherein a distalportion of the catheter is shaped to define a first lateral opening anda second lateral opening, and wherein an angle between (a) a first linerunning between the first and second lateral openings, and (b) a secondline that is parallel to a central longitudinal axis of the catheterwhen the catheter is straight, is between 30 and 150 degrees; a flexiblelongitudinal member that passes (a) from a proximal portion of thecatheter to the distal portion of the catheter via the first channel,(b) out of the first channel via the first lateral opening, (c) into thesecond channel via the second lateral opening, and (d) from the distalportion of the catheter to the proximal portion of the catheter via thesecond channel; a needle shaped to be slidably disposed within thecatheter lumen; a dilator element shaped to be slidably disposed withinthe catheter lumen, wherein the dilator element is shaped to define adilator lumen; and a dilator tip disposed at a distal end of the dilatorelement, wherein the dilator tip is configured to dilate an openingcreated by the needle.
 2. The apparatus according to claim 1, whereinthe angle between the first and second lines is between 60 and 120degrees.
 3. The apparatus according to claim 2, wherein the anglebetween the first and second lines is between 80 and 100 degrees.
 4. Theapparatus according to claim 1, wherein the first and second openingsare separated from one another by an angle of 170-190 degrees measuredalong a circumference of the catheter.
 5. The apparatus according toclaim 1, wherein the needle is shaped to be slidably disposed within thedilator lumen.
 6. The apparatus according to claim 1, wherein theflexible longitudinal member is mechanically resilient.
 7. The apparatusaccording to claim 1, wherein a diameter of the flexible longitudinalmember is between 0.1 and 0.5 mm.
 8. The apparatus according to claim 1,wherein the flexible longitudinal member comprises a wire.
 9. Theapparatus according to claim 1, wherein the flexible longitudinal membercomprises a material selected from the group consisting of: nitinol,stainless steel, and chromium cobalt.
 10. The apparatus according toclaim 1, wherein the flexible longitudinal member is configured to bedeployed such that, in an absence of any force applied to the deployedportion of the flexible longitudinal member by an element that is notpart of the apparatus, a deployment angle of the flexible longitudinalmember is between 10 and 80 degrees, and wherein the deployment angle isbetween (a) a vector that is (i) tangent to the flexible longitudinalmember at an exit point of the flexible longitudinal member from thecatheter, and (ii) directed away from the catheter, and (b) adistally-directed vector that is parallel to a longitudinal axis of thecatheter at the exit point.
 11. The apparatus according to claim 10,wherein the flexible longitudinal member is configured to be deployedsuch that, in the absence of any force applied to the deployed portionof the flexible longitudinal member by an element that is not part ofthe apparatus, the deployment angle is between 30 and 60 degrees. 12.The apparatus according to claim 1, wherein the flexible longitudinalmember is radiopaque.
 13. The apparatus according to claim 1, furthercomprising a plurality of radiopaque markers coupled to the flexiblelongitudinal member.
 14. Apparatus comprising: a catheter shaped todefine a catheter lumen, wherein a wall of the catheter (a) comprises abraided portion, and (b) is shaped to define a firstlongitudinally-running channel through the wall and a secondlongitudinally-running channel through the wall, and wherein a distalportion of the catheter is shaped to define a first lateral opening anda second lateral opening, and wherein an angle between (a) a first linerunning between the first and second lateral openings, and (b) a secondline that is parallel to a central longitudinal axis of the catheterwhen the catheter is straight, is between 30 and 150 degrees; a flexiblelongitudinal member that passes (a) from a proximal portion of thecatheter to the distal portion of the catheter via the first channel,(b) out of the first channel via the first lateral opening, (c) into thesecond channel via the second lateral opening, and (d) from the distalportion of the catheter to the proximal portion of the catheter via thesecond channel; and a needle shaped to be slidably disposed within thecatheter lumen, wherein the needle is hollow, and comprises (a) aproximal portion, and (b) a helical distal portion, and wherein theapparatus further comprises a fluid-impermeable cover surrounding thehelical distal portion of the needle.
 15. Apparatus comprising: acatheter shaped to define a catheter lumen, wherein a wall of thecatheter (a) comprises a braided portion, and (b) is shaped to define afirst longitudinally-running channel through the wall and a secondlongitudinally-running channel through the wall, and wherein a distalportion of the catheter is shaped to define a first lateral opening anda second lateral opening, and wherein an angle between (a) a first linerunning between the first and second lateral openings, and (b) a secondline that is parallel to a central longitudinal axis of the catheterwhen the catheter is straight, is between 30 and 150 degrees; a flexiblelongitudinal member that passes (a) from a proximal portion of thecatheter to the distal portion of the catheter via the first channel,(b) out of the first channel via the first lateral opening, (c) into thesecond channel via the second lateral opening, and (d) from the distalportion of the catheter to the proximal portion of the catheter via thesecond channel; and a needle shaped to be slidably disposed within thecatheter lumen, wherein the needle is hollow, and comprises (a) aproximal portion, and (b) a distal portion that is more flexible thanthe proximal portion, and wherein the apparatus further comprises afluid-impermeable cover surrounding the distal portion of the needle.16. The apparatus according to claim 15, further comprising: a dilatorelement shaped to be slidably disposed within the catheter lumen,wherein the dilator element is shaped to define a dilator lumen; and adilator tip disposed at a distal end of the dilator element, wherein thedilator tip is configured to dilate an opening created by the needle.17. Apparatus comprising: a catheter shaped to define a catheter lumen,wherein a wall of the catheter (a) comprises a braided portion, and (b)is shaped to define a first longitudinally-running channel through thewall and a second longitudinally-running channel through the wall, andwherein a distal portion of the catheter is shaped to define a firstlateral opening and a second lateral opening, and wherein an anglebetween (a) a first line running between the first and second lateralopenings, and (b) a second line that is parallel to a centrallongitudinal axis of the catheter when the catheter is straight, isbetween 30 and 150 degrees; a flexible longitudinal member that passes(a) from a proximal portion of the catheter to the distal portion of thecatheter via the first channel, (b) out of the first channel via thefirst lateral opening, (c) into the second channel via the secondlateral opening, and (d) from the distal portion of the catheter to theproximal portion of the catheter via the second channel; and a needleshaped to be slidably disposed within the catheter lumen, wherein theneedle is hollow, and comprises (a) a proximal portion, and (b) a distalportion comprising a wall that is shaped to define a plurality ofopenings that pass completely therethrough, and wherein the apparatusfurther comprises a fluid-impermeable cover surrounding the distalportion of the needle.
 18. Apparatus comprising: a catheter shaped todefine a catheter lumen, wherein a wall of the catheter (a) comprises abraided portion, and (b) is shaped to define a firstlongitudinally-running channel through the wall and a secondlongitudinally-running channel through the wall, and wherein a distalportion of the catheter is shaped to define a first lateral opening anda second lateral opening, and wherein an angle between (a) a first linerunning between the first and second lateral openings, and (b) a secondline that is parallel to a central longitudinal axis of the catheterwhen the catheter is straight, is between 30 and 150 degrees; a flexiblelongitudinal member that passes (a) from a proximal portion of thecatheter to the distal portion of the catheter via the first channel,(b) out of the first channel via the first lateral opening, (c) into thesecond channel via the second lateral opening, and (d) from the distalportion of the catheter to the proximal portion of the catheter via thesecond channel; and a needle shaped to be slidably disposed within thecatheter lumen, wherein the needle is hollow, and comprises (a) aproximal portion, and (b) a distal portion comprising an elastomerictube having an outer surface, an inner surface, and an interior portionbetween the outer and inner surfaces that is selected from the groupconsisting of: a braided metal interior, and a coiled metal interior.19. Apparatus comprising: a catheter shaped to define a catheter lumen,wherein a wall of the catheter (a) comprises a braided portion, and (b)is shaped to define a first longitudinally-running channel through thewall and a second longitudinally-running channel through the wall, andwherein a distal portion of the catheter is shaped to define a firstlateral opening and a second lateral opening, and wherein an anglebetween (a) a first line running between the first and second lateralopenings, and (b) a second line that is parallel to a centrallongitudinal axis of the catheter when the catheter is straight, isbetween 30 and 150 degrees; a flexible longitudinal member that passes(a) from a proximal portion of the catheter to the distal portion of thecatheter via the first channel, (b) out of the first channel via thefirst lateral opening, (c) into the second channel via the secondlateral opening, and (d) from the distal portion of the catheter to theproximal portion of the catheter via the second channel; and a needleshaped to be slidably disposed within the catheter lumen, wherein theneedle is hollow, and comprises: a proximal portion having an outerdiameter between 0.7 and 3 mm, a length between 650 and 1200 mm, and awall thickness between 0.1 and 0.3 mm; and a distal portion at leastpartially made of nitinol, the distal portion having an outer diameterbetween 0.5 and 1.5 mm and a length between 30 and 200 mm.
 20. Apparatuscomprising: a catheter shaped to define a catheter lumen, wherein a wallof the catheter (a) comprises a braided portion, and (b) is shaped todefine a first longitudinally-running channel through the wall and asecond longitudinally-running channel through the walk and wherein adistal portion of the catheter is shaped to define a first lateralopening and a second lateral opening, and wherein an angle between (a) afirst line running between the first and second lateral openings, and(b) a second line that is parallel to a central longitudinal axis of thecatheter when the catheter is straight is between 30 and 150 degrees: aflexible longitudinal member that passes (a) from a proximal portion ofthe catheter to the distal portion of the catheter via the first channel(b) out of the first channel via the first lateral opening, (c) into thesecond channel via the second lateral opening, and (d) from the distalportion of the catheter to the proximal portion of the catheter via thesecond channel: a needle shaped to be slidably disposed within thecatheter lumen, wherein the needle is electrically conductive; one ormore conductors; and a controller, which is coupled to the needle by theone or more conductors, and which is configured to drive the needle toapply energy capable of creating a hole through tissue.